1. Rhabdophane from a rare-earth occurrence, Valley County;Adams;U.S. Geol. Surv., Prof. Paper,1968
2. Distribution of lanthanides in minerals;Adams;U.S. Geol. Surv., Prof. Paper,1969
3. Thalenite from Teller County, Colorado;Adams;U.S. Geol. Surv., Prof. Paper,1962
4. A new find of gagarinite;Akelin;Dokl. Acad. Sci. U.S.S.R., Earth Sci. Sect.,1963
5. Rare-Earth Elements in the Sredna Gora Granitoids and the Pegmatites Connected with them in the Region of Koprivshtitsa and Strelcha;Aleksiev;Izv. Geol. Inst., Bulg. Akad. Nauk, Ser. Geokhim., Mineral., Petrogr.,1970